Need for measurements in the lower atmosphere

Areas of investigation that are discussed include: the relative importance of the turbopause versus winds in determining the composition of the thermosphere; the mechanism of the coupling between the mesosphere and the thermosphere and how important wave dissipation is in this coupling; and the morphology and variation of magnetospheric energy inputs at high latitudes. The need to investigate the propagation characteristics of atmospheric gravity waves in the altitude region between 100 and 200 km is emphasized.